IPA: //ʌnˈdaɪdʒɛstɪbəl//
KK: /ʌnˈdaɪdʒɛstəbəl/
Something that cannot be digested or processed by the body.
Some foods are undigestible for certain people, causing discomfort.
Undigestible → It is formed from "un-" (meaning not) and "digestible" (from Latin "digestus", meaning to break down or process). The word "undigestible" means not able to be broken down or processed by the body.
Think of 'not' ('un-') being able to 'break down' ('digestible') — that's why undigestible means something that cannot be processed.